Electrostatic transmission mechanism

ABSTRACT

An electrostatic transmission mechanism can be adopted for use in data media recorders such as printers, facsimile machines, or scanners to transport media. The invention has a feed roller with an electrostatic field generator located therein to generate static electricity on the surface of the feed roller to attract and transport media. The invention can eliminate the disadvantages of conventional transmission mechanisms such as crumpled paper resulting from the pressing of the feed rollers, star wheel tracks on the paper caused by the star wheels, etc.

FIELD OF THE INVENTION

[0001] The invention relates to a transmission mechanism adopted for usein data media recorders such as printers, plotters, scanners,Multi-Function Peripherals (MFP, Copiers) and the like, and particularlyto a transmission mechanism that utilizes static electricity totransport papers.

BACKGROUND OF THE INVENTION

[0002] Data media recorders are very popular these days. The equipmentto print media data on paper or to convert media data on paper todigital data for storage includes printers (Inkjet, Laser, or Impactprinters), plotters, scanners, and Multi-Function Peripherals (MFP,Copiers). These all need a transmission mechanism to transport the media(paper), whether feeding (delivering paper), printing (scanning) on themiddle frame, or discharging (paper).

[0003] The current data media recorders being used in printers mostlyadopt feed rollers, deflators or star wheels to transport the media forfeeding, printing or discharging. Although these mechanisms aim atconveying or positioning the media in a flat manner, printing quality isstill not desirable. For instance, papers transported by two feedrollers become crumpled (as shown in FIG. 1A). The dischargingmechanisms that use star wheels 6 leave star wheel tracks on the paperand seriously affect the printing quality (referring to FIG. 1B).

[0004] There are other paper feeding mechanisms that employ geartransmission. In order to match the size of the paper, and to make thepaper flat and smooth in the entire conveying process, the size of themechanism becomes substantially larger (as shown in FIG. 1C), whichincurs higher costs. Moreover, transmission mechanisms used in plottersemploy air fans to create vacuum suction to place the paper on theprinting middle frame, which generates substantial noise.

SUMMARY OF THE INVENTION

[0005] The object of the invention is to provide an electrostatictransmission mechanism to resolve the aforesaid disadvantages. Theinvention employs static electricity to attract media onto the feedroller in a flat and smooth manner to achieve high quality printing andto transport or re-direct the media.

[0006] The electrostatic transmission mechanism of the invention isadopted on various data media recorders for media feeding, printing anddischarging in static printing operations and also for dynamictransporting. The transmission mechanism includes a feed roller and anelectrostatic field generator. The electrostatic field generatorgenerates a reaction on the feed roller and produces static electricityon the roller surface. Therefore the feed roller can transport the mediawithout employing the complicated conventional designs of feed rollersor star wheels. Cost can be dramatically reduced and printing qualitycan also be improved.

[0007] The electrostatic field generator is formed by laying conductivewires on the feed roller surface. A single circuit wiring is used toform two conductors to connect respectively to two poles. The surface iscoated with an insulation layer. Through deploying different types anddensities of wiring configuration and different widths of insulation,power intensity generated by the electrostatic field generator may becontrolled to enable the feed roller to generate different electrostaticattraction forces to transport or re-direct the media.

[0008] The foregoing, as well as additional objects, features andadvantages of the invention will be more readily apparent from thefollowing detailed description, which proceeds with reference to theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] FIGS. 1A-1C are schematic views of disadvantages of conventionaltransmission mechanisms;

[0010]FIG. 2 is a schematic view of the invention;

[0011] FIGS. 3A-3C are schematic views of wiring configurations of theinvention;

[0012]FIG. 4 is a schematic view of the invention, adopted on a printingmiddle frame;

[0013]FIG. 5 is a schematic view of the print head and the paper,according to FIG. 4;

[0014]FIG. 6 is a schematic view of the invention, adopted on a paperdischarging mechanism; and

[0015]FIGS. 7A, 7B and 8 are schematic views of the invention, showingre-direction of paper transportation.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0016] The electrostatic transmission mechanism of the inventionincludes a feed roller and an electrostatic field generator. Theelectrostatic field generator generates a reaction on the feed rollerand produces an electrostatic field on the roller surface. Therefore thefeed roller can attract the media to be transported. Through therotation of the feed roller, the media may be moved as desired. Anelectrostatic field may be generated by many methods. The followingdepicts one embodiment for elaboration of the invention.

[0017] Referring to FIG. 2, a feed roller 10 has its surface coated ortaped with conductive wires 21. The conductive wires 21 are coated andcovered by an insulation layer 22. Conductive wires 21 a and 21 b crosseach other and connect to a positive pole and a negative pole (not shownin the drawing) of a power supply. The wiring configuration may be aband shape (as shown in FIG. 3A), a wave shape (as shown in FIG. 3B), ora saw shape (as shown in FIG. 3C). The wiring may be parallel with thespindle direction of the feed roller 10, or form an angle with thespindle direction. In principle, the conductive wires 21 a and 21 b mustbe crossed with each other to generate the electrostatic field on thesurface of the feed roller 10. The intensity of the electrostatic fieldis controlled by different types and densities of the wiringconfiguration and different widths of insulation layer 22. Designs ofthe wiring configuration, in addition to considering the intensity ofthe electrostatic field, also depend on deploying environments,locations and utilization. And the intensity of the electrostatic fieldis also determined by the voltage difference output of the power supply.

[0018] When adopted on a printing middle frame as shown in FIG. 4, thefeed rollers 11 and 12 have an electrostatic field and generateelectrostatic force to attract a piece of paper 7 to their surfaces.Then the feed rollers 11 and 12 rotate to convey the paper 7. Such adesign does not require that the paper is moved to a selected locationbehind the print head 2 as the discharging system of the conventionalstar wheel 6 does (comparing with FIG. 1C), so it does not need manyintermediate transmission gears. As a result, the length of the printingmiddle frame may be shortened, and cost can be reduced. Noise generatedby the intermediate transmission gears is also reduced. In addition, asthe paper 7 is transported by a single feed roller 11 (12), papercrumpling can be avoided. Thus the paper 7 becomes flat and smooth. Thegap G between the print head 2 and the paper 7 also may be shrunk (asshown in FIG. 5). As a result, printing quality may be improved(comparing with FIG. 1A).

[0019] By the same token, when deploying the invention on a paperdischarging mechanism, the feed roller 12 with an electrostatic fieldattracts the paper 7 and discharges the printed paper 7. There is nopress operation, as required by the star wheels 6. Hence the printedpaper does not have the star wheel tracks that might otherwise occurwhen the star wheels 6 roll over the fresh printing data on the paper 7(shown in FIGS. 1B and 6).

[0020] In addition, Referring to FIGS. 7A and 7B, the feed rollers 13and 14 with static electricity generate a stretching force on the paper7 and change the direction of paper movement. In other words, bydeploying a roller seat 17 (as shown in FIG. 8) to encase and anchor thefeed roller 14, and to form selected exposing areas on the feed roller14, the feed roller 14 with static electricity can attract the paper 7.Then the rotating feed roller 14 can move the paper 7 to a selectedlocation A, and the paper 7 leaves the feed roller 14. When the paper 7reaches location B, the paper 7 bounces upwards due to its own tension.When the paper 7 reaches location C, it completely separates from thefeed roller 14.

[0021] By means of the construction set forth above, the electrostatictransmission mechanism of the invention can generate static electricityon the feed roller through the electrostatic field generator forattracting and transporting the media. In addition, it provides thefollowing functions:

[0022] 1. By employing the attraction of static electricity, the mediaon the printing middle frame is flat and smooth. The gap between theprint head and the media may be reduced to improve printing quality.

[0023] 2. The length of the printing middle frame may be reduced tolower cost.

[0024] 3. The star wheel tracks produced by the star wheels in the paperdischarging mechanism may be eliminated to improve printing quality.

[0025] 4. The media transporting mechanism requires fewer elements.

[0026] 5. The principle of attraction of static electricity of a singlefeed roller may be used for re-direction of the media without usingmultiple rollers.

[0027] 6. The intensity of the electrostatic field may be controlled bya single circuit, different configurations and density of wiring, andthickness of the insulation layer.

[0028] While the preferred embodiment of the invention has been setforth for the purpose of disclosure, modifications of the disclosedembodiment of the invention as well as other embodiments thereof mayoccur to those skilled in the art. Accordingly, the appended claims areintended to cover all embodiments which do not depart from the spiritand scope of the invention.

What is claimed is:
 1. An electrostatic transmission mechanism for datamedia recorders to transport a paper through feeding, printing anddischarging operations, comprising: a feed roller driven to rotate by adriving apparatus of the data media recorders to transport the paper;and an electrostatic field generator connecting electrically to the feedroller to generate static electricity on the surface of the roller toattract the paper and to allow the paper to move on the surface of thefeed roller in a flat and smooth manner.
 2. The electrostatictransmission mechanism of claim 1, wherein the electrostatic fieldgenerator includes: a power supply which has a positive pole andnegative pole; and two pairs of conductive wires crossing with oneanother and being laid on the surface of the feed roller, and connectingrespectively to the positive pole and the negative pole of the powersupply for generating static electricity.
 3. The electrostatictransmission mechanism of claim 2, wherein the conductive wires arecovered by an insulation layer.
 4. The electrostatic transmissionmechanism of claim 3, wherein the intensity of the electrostatic fieldis determined by the thickness of the insulation layer.
 5. Theelectrostatic transmission mechanism of claim 2, wherein the intensityof the electrostatic field is determined by the output voltage of thepower supply.
 6. The electrostatic transmission mechanism of claim 2,wherein the intensity of the electrostatic field is determined by thedensity of the conductive wires and wiring configurations of theconductive wires.
 7. The electrostatic transmission mechanism of claim 2further having a roller seat to control exposed areas of the feed rollerand re-direction of the paper transportation.
 8. An electrostatictransmission mechanism for data media recorders having a feed roller totransport media required by the data media recorders, characterized by:two pairs of conductive wires crossing with one another and being laidon the surface of the feed roller and said conductive wires connectingto a power supply to generate static electricity on the feed roller toattract and transport the media.
 9. The electrostatic transmissionmechanism of claim 8, wherein the conductive wires are covered by aninsulation layer.
 10. The electrostatic transmission mechanism of claim9, wherein the intensity of the electrostatic field is determined by thethickness of the insulation layer.
 11. The electrostatic transmissionmechanism of claim 8, wherein the intensity of the electrostatic fieldis determined by the density of the conductive wires and wiringconfigurations of the conductive wires.
 12. The electrostatictransmission mechanism of claim 8 further having a roller seat tocontrol exposed areas of the feed roller and re-direction of the papertransportation.